Re: [PATCH 1/2] thermal/core: Hardening the self-encapsulation

From: Thierry Reding
Date: Thu Oct 12 2023 - 10:30:27 EST


On Thu, Oct 12, 2023 at 03:14:23PM +0200, Daniel Lezcano wrote:
>
> Hi Lukasz,
>
> On 12/10/2023 14:01, Lukasz Luba wrote:
> > Hi Daniel,
> >
> > On 10/12/23 11:26, Daniel Lezcano wrote:
> > > The thermal private header has leaked all around the drivers which
> > > interacted with the core internals. The thermal zone structure which
> > > was part of the exported header led also to a leakage of the fields
> > > into the different drivers, making very difficult to improve the core
> > > code without having to change the drivers.
> > >
> > > Now we mostly fixed how the thermal drivers were interacting with the
> > > thermal zones (actually fixed how they should not interact). The
> > > thermal zone structure will be moved to the private thermal core
> > > header. This header has been removed from the different drivers and
> > > must belong to the core code only. In order to prevent this private
> > > header to be included again in the drivers, make explicit only the
> > > core code can include this header by defining a THERMAL_CORE_SUBSYS
> > > macro. The private header will contain a check against this macro.
> > >
> > > The Tegra SoCtherm driver needs to access thermal_core.h to have the
> > > get_thermal_instance() function definition. It is the only one
> > > remaining driver which need to access the thermal_core.h header, so
> > > the check will emit a warning at compilation time.
> > >
> > > Thierry Reding is reworking the driver to get rid of this function [1]
> > > and thus when the changes will be merged, the compilation warning will
> > > be converted to a compilation error, closing definitively the door to
> > > the drivers willing to play with the thermal zone device internals.
> >
> > That looks like a good idea. Although, shouldn't we avoid the
> > compilation warnings and just first merge the fixes for drivers?
>
> Yes, we should but there is the series for nvidia (pointed in the changelog)
> which need a slight refresh for the bindings AFAIR. That series is since
> March 2023 and Thierry seems busy [1]. I'm holding the hardening since then.
>
> So I don't know how to make progress on this? I was assuming we can merge
> this series and let the compiler recall what has to be fixed.
>
> [1] https://lore.kernel.org/all/ZK14edZUih1kH_sZ@orome/
>
> and as soon as it is fixed, we convert the WARNING to ERROR :P

Yeah, sorry about that. This has been plagued by bad luck. Since then
the device that I need to test this on broke and it then took a while to
get a new one. I still need to find time to set this up and do some more
extensive testing to make sure I haven't regressed anything.

Thierry

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